Further enhancements to a novel optical packaging technology for datalinks are reported. Evolutionary improvements in the design, processes, and implementations of the integrated lensireceptacle have been made. A new mechanical package for FDDI using the lensireceptacle has been designed in addition to the original SC-duplex and SCiST-simplex styles. Details of the mechanical and optical design, production issues, and performance statistics are reported.The basis for this low cost packaging approach is independent integration of the optical connector and electronic functions. Precision polymer molding technology has been used to design a multifunction element providing connector ferrule seating, optoelectronic device and fiber plane placement, connector feature integration, case and process sealing, and efficient optical coupling at right angles to the fiber axis. The last feature allows for assembly of the optoelectronic devices on the same board with the circuit components. Besides ease ,of testing and cost reduction, eliminating the TO header in this way improves electrical and thermal performance.

Although the progress of short wavelength VCSEL-based parallel optical links has been published by several groups [l][2], the use of highly reliable long wavelength LEDs has recently been investigated as a viable option for applications requiring 622 Mb/s or less. This paper presents an LED based parallel optical link using a unique method for optical modeling to improve coupling efficiency between light sources and waveguides. Figure 1 shows the schematic of the LED based parallel optical link. There are five transmitter channels (LED array) and five receiver channels (PIN array). Polyguide" optical waveguides[3] with 45" mirrors are used to couple light between the arrays and the ribbon fiber through an MT style ferrule connector. An optical model utilizing graphical ray path representation, power tracking of each ray, and accurate modeling of the LED emission has been developed to investigate and improve the coupling efficiency [4]. Figure 2 shows three-dimensional and cross-sectional views of coupled rays determined by this model. The integral micro-lens of the LED used in this experiment was characterized using a noncontact profilometer to provide accurate verification of the model. The software generates 160,000 rays emanating from the LED heterojunction active area disk with a Lambertian distribution. Ray/surface intersection points and direction cosines are calculated for each surface. Refracted or reflected angle, Fresnel reflection, and linear absorption are then calculated along each ray at each surface progressively. The coupling efficiency is calculated as the ratio of the power sum of the guided rays to the total number of rays emitted from the LED. The entire calculation is repeated for each off axis position of the LED to obtain longitudinal and lateral coupling curves . Figures 3, 4, and 5 compare the simulated and actual LED to Polyguide coupling versus offset in z, x, and y axes respectively. The average difference between experimental and theoretical values is 2.2%. Figure 6 shows the relative coupled power measured as a function of x and y axes offsets. A preliminary study shows that the total power coupled into 62.5 pm fiber is approximately -18.5 dBm including Polyguide and connector losses. Combined with typical receiver performance, the link is suitable for transmission lengths on the order of several hundred meters. This work is based on LEDs which have a measured activation energy of 0.9 eV and a qualified -1.5 dB MTTF of 1.2 x lo1' hours (A= .08 FITS) at 25 "C. These devices were operated at 155 Mb/s but are capable of 270 Mb/s operation.Additionally, LEDs operating at 622 Mb/s have been demonstrated[5] and will be used in future versions of this link.In summary, a prototype parallel optical data link based on LEDs and planar waveguide technology has been developed, modeled, and characterized. Close agreement between the theoretical values calculated from the model and the measured values has been achieved. This approach provides a practical alternative for many fiber communication a...

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Many of the functions necessary for fiber optic coupling in data link applications have been incorporated into one opto-mechanical device called a lensheceptacle. The lens/receptacle enables the assembly of data links with reduced parts count, simplified assembly, lower cost, and streamlined testing with many performance advantages. The packaging consistent with this lens can accommodate data rates in excess of 600 M bls . This paper outlines the design of the lens/receptacle while highlighting the performance benefits of the package as a whole. Performance results presented are on FDDl compliant pre-production prototypes operating at 125 Mb/s at h = 1330 nm. Jntroduction;The availability of inexpensive fiber optic data communication equipment will enable the realization of wide area, shared resource, computer networks. The adoption of the Fiber Distributed Data Interface (FDDI) standard [l], including recent work toward a Low Cost FDDl standard, guides the path to the data communication superhighways of the future. Data link packaging efforts to date [2,3], including so called ''low cost" packaging, have concentrated primarily on integrated circuit packaging and consolidation. The trusty "TO" header has been consistently relied upon to house active devices and mate with expensive optical coupling elements such as GRIN lenses and split sleeves. The header has also seen increased integration by housing preamplifier circuits. While this approach is technically sound, it shifts the cost from the driveheceive electronics to the active device mount (ADM).An approach to manufacturing cost reduction has been taken which involves optical solutions to the ADM problem. The introduction of an integrally molded lensheceptacle element which performs fiber-receiving, lightcoupling, and light-bending functions eliminates the need for headers by allowing tight integration of all electronics and active devices on a pre-tested board assembly. The multifunction precision molding further